Auxiliary supporting roller arrangement for pallet trucks



Fak E5, 1949.. l. F. scHREcK AUXILIARY SUPPORTING ROLLER ARRANGEMENT FORPALLET TRUCKS Filed May s, 194e v x lull .lnk

Patented Feb. 15,v 1949 UNITED STATES PATENT oFFlcEp AUXILIARYSUPPORTING ROLLER AR- RANGEMENT FOR PALLET TRUCKS Irvin F. Schreck,Cleveland Heights, Ohio Application May 3, 1946, Serial No. 667,131

(Cl. 280-44) i Claims.

This invention relates to lift trucks which have roller supporting loadcarrying members that are adjustable to a position close to a licorsurface, and particularly to trucks having load lifting members that canbe backed under a pallet and elevated to lift and carry the pallet.

The load engaging portions of trucks such as pallet trucks must besupported upon rollers of small diameter in order to enable them toenter the space beneath the pallet. Because of the small diameter of therollers, difficulty is often experienced in moving such trucks overirregularities on a floor surface and in moving the trucks onto and olffrom elevator platforms. It is difficult to stop the ordinary elevatorwith its plat- V form at the exact level of a oor. If the elevatorplatform is offset an inch or so above the oor surface difficulty isexperienced in moving a truck onto the elevator platform, and if theplatform is oii'set an inch or so below the iloor surface diculty isexperienced in moving a truck off of the elevator platform.

The present invention has for its object to provide means forfacilitating the travel of trucks of the character referred to over anirregular floor surface, or to or from an elevator platform.

With the above and other objects in view, the invention may be said tocomprise the device as illustrated in the accompanying drawings,hereinafter described and particularly set forth in the appended claims,together with such variations and modifications thereof as will beapparent to one skilled in the art to which the invention pertains.

Reference should be had to the accompanying drawings forming a part ofthis specication, in which:

Figure l is a fragmentary plan view of a pallet truck to which theinvention is applied;

Fig. 2 is a side elevation of the load'lifting portion of the truck;

Fig. 3 is a section taken on the line indicated at 3-3 in Fig. 2; Y

Fig.v4 is a section taken onthe'line indicated at 4-4 in Fig. 3, and

Fig. 5 is a section taken on the line indicated at 5-5 in Fig. 4.

In the accompanying drawings the invention is shown applied to a truckof the type disclosed in my Patent No. 2,359,493, granted October 3,1944. A tractor` body I is supported upon a front wheel' 2 which isswiveled in the tractor body and motor driven and a steering handle 3 ispivoted to the turntable in which the supporting wheel is mounted. Thetruck is provided with a vertically movable load carrier 4 which isadapted to be moved vertically by means of a uid pressure cylinder 5mounted upon the rear end of the tractor body. The load carrier 4 hasforwardly projecting pallet engaging arms 6 which are horizontallydisposedvand which are provided with supporting legs 'I adjacent theirrear ends. The supporting legs are pivoted to swing vertically beneaththe arms 6 and means is provided for automatically swinging the legs 'Idownwardly as the carrier 4 is being elevated, the legs 1 being actuatedby means of links 8 which extend forwardly to levers 9 connected to thetractor body I and load carrier 4 to be automatically actuated when thecarrier is lifted. The pivoted supporting legs 'I are in the form ofdownwardly facing channels having side plates I0 and a flat top plate IIwhich may be welded together to provide a uni.. tary structure. A pivotpin I2 is rigidly secured to the forward end of the leg 1 and isjournaled in a bearing member I3 attached to the under side of the arm6.

Each of the supporting legs is provided adjacent its free end withtrunnions I4 which are carried bythe side plates IIJ exteriorly thereof.The trunnions I4 are coaxial and disposed parallel withan axle I5 thatis journaled in a widened portion IIB of the side plates I Il inwardlyof the trunnions I4. A main supporting roller I'I is mounted upon ballbearings I8 between the side plates I0 and these rollers engage theiioor in all positions of the supporting leg. Booster rollers I9 whichmay be identical with or similar to the bearings. I8 are mounted uponthe trunnions I4. lThe auxiliary or booster rollers I9 are of lessdiameter than the rollers I5 but by reason ofthe fact that the trunnionsI4 are disposed alongside the roller I'I outwardly of the axle I5, therollers I 9 move toward and away from the oor as the legs are swungdownwardly and upwardly and are in close proximity to the floor surfacewhen the legs 1 are swung down to their lowermost positions. Theauxiliary or booster rollers I9 must be consider'- ably smaller than therollers I'I so that they will not interfere with the required movementsof the legs 'I by engagement with the floor or arm 6, but they should belarge enough to have effective rolling action and the desired loadcarrying eapacity. .In order to provide sufficient space between thetrunnions I 4 and the floor to accommodate auxiliary booster rollers ofthe desired size, the axis of the trunnions I 4 is above the plane thatincludes the axis of the roller I1 and the pivotal axis of the leg I inall positions of the leg. The rollers I9 being disposed rearwardly ofthe axle I and spaced slightly above the floor surface, will engage witha ledge projecting above the portion of the floor surface engaged by theroller I1 before the roller I1 engages to momentarily support andslightly lift the load before the roller I1 engages the ledge. Since thetreads of the booster rollers extend across the tread of the main rollervery close to the point of engagement of the tread of the main rollerwith the floor the booster rollers and the main roller cannot straddle astick or rod or a narrow ridge on the floor surface and in passing oversuch a stick, rod or ridge the load is transferred smoothly from thevbooster roller to the main roller. For example,:in-moving'a truck ontoor off of an elevator platform, the rollers I9 of each leg serve asboosters toliftthe roller I1 and assist it to pass over the ledge whenthere is a slight difference in the elevation of the platform and floorsurface.

The top of the leg 1 is Apreferably at so that in the lcwermost'positionof the loadl carrying arms 6'=the .top ofltlie'legV 1 rests against.the'ilat under side `of the arms 6 and, in'forder -to ypermit therollers'I1 to 'be of the greatest possible diameter, these rollersproject slightly above the tops of the arms 1-arrd into theslots 20formed inthe arms 6 when the arms lzare in their lowermost position, `asshown in Fig. 2.

`A`It is to tbe understood that variations and modifications of thespeciiic devices herein shown anddescribed for purposes `ofillustration,- may be made without-departing from thevspirit of the'invention.

'What I claim Yis:

'1.1Alift truck having a 'vertically yadjustable loadcar-rying member,'means'for adjusting-said member including a supporting leg pivotedtosaid. member and serving as a lift lever, and' main and auxiliarysupporting rollers carried 'bysaid leg,

saidrollers `beirig'r'r'iounted side by Side -wlth 'their axes'parallelandat different distances from the pivot of said leg, said main rollerextendingpast the axis'othe` auxiliary roller and 'being engageable withthe floor at all times land said auxiliary roller being sopositionedfwith respect to the-main roller that it moves'toward and awayfrom the oor lduring pivotal movements of the leg and is supported outof engagement with-the floor but in closev proximity to thefloor inoneextremeposition of said leg. y

2. 'A lift vtruck havinga vertically adjustable load carrying member,Ymeansfor adjusting said member -including asupporting leg pivoted tosaid member'and serving as a lift lever, andmainl and auxiliarysupporting rollers carried by said leg, said Vauxiliary roller beingmounted beside'the main roller with its axis parallel to the axis of themain roller and fartherfrom4 the leg pivot, said main roller extendingvpast vthe axis of theI auxillary roller and Vbeing'engageable with4tlie floor in all positions of adjustment `of the leg andsaid auxiliaryroller being so positioned rthat it j is shifted toward -the floor assaid leg is swung downwardly and is in close proximity to the'floor inthe lowermost position of vsaid supportingl'eg.

TF3. Af lift truck' having a vertically adjustable load carrying member,means for adjusting said member including an'adjustable supporting legpivoted at one end to the under side `of said memberand'movabledownwardly from a position in which it lies against the under side fsaid member, said leg having laterally spaced'arms provided 4 withoutwardly projecting trunnions adjacent their outer ends, an axlemounted in said arms inwardly of said trunnions, a main supportingroller mounted on said axle and between said arms, and extending pastsaid trunnions, and auxiliary rollers mounted on said trunnions andalongside said main roller, said auxiliary rollers being so positionedthat they are shifted toward the floor as the leg is swung downwardlyand are brought into close 4proximity to the floor when the leg is inits lowermost position.

4. In a lift truck having a vertically adjustable load carrying memberhaving a flat bottom face,

anfadjustable supporting leg pivoted to the under side of said member toswing vertically and having a -flatlongitudinal face engageable withsaid flat bottom face of said member, said leg having parallel sideplates provided with axially aligned trunn'lons adjacent their freeends, an axle journaled in said side plates inwardly of said trunnions,amain roller mounted on `saidaxle between said plates and'extending'past said trun-a nions and :booster rollers of smallerdiameterthan said main' roller mounted `on said trunnions alongside saidr mainroller, said booster rollers being so positioned that they are spacedslightly abovethe iioor'in the lower-most position of the leg andbeneath said'flat bottom face of theload carrying member in theuppermost position -of the leg.

15. In a pallet truck, a horizontally disposed vertically movable loadcarrying arm, supporting means for said arm including a lifting andsupporting leg beneath the arm and connected at one end 'to the arm toswingabout a horizontal pivotal axis,-said leg'being vmovable about itspivotal axis downwardly from a position against the under side of thearm to a lowermost inclined position to elevate said arm to loadcarrying position, a supporting roller mounted cnsaid leg adjacent itsfree .end'with its axis'parallel to saidupivotal axis and engagingthefloor in all positions of theileg, and an auxiliary roller of lessdiameter than the supporting rollermounted on said leg to turn about`an' axis parallel to the axis of the supportingroller and `at `a greaterUdistance from'said pivotal'axis than the axis of the supporting roller,the axis of said auxiliary roller being above the plane of said pivotalaxis and said supporting roller axis-inail positions of the leg,theposition and size of said auxiliary roller being suchthat itsperiphery'is. closely adjacent but out of contact with the floor inthelowermost position of the leg and-closely adjacent the arm in theuppermost position of the leg.

' IRVIN F. SCI-IRECK.

REFERENCES CITED 'Il'ie following references are of `record inthe le ofthisfpatent:

UNITED STATES PATENTS Number Name `Date 2,178,647 Raymond et al. .f-Nov. 7,1939 52,234,925 Hastingsglr Mar. 11,1941 2,242,326 Quayle May20, '19415 '2,243,915 Mueller June'3, 1941 2,359,493 Schreck Oct. 3,1944

' FOREIGN PATENTS lbuil'iber Country Date 106,353 Switzerland Sept. 16,1924

